Margin stop made of a synthetic material

ABSTRACT

A margin stop for stopping the paper carriage of a typewriter in an end position, is constructed as an integral piece of a synthetic material including a tooth, and a spring tongue engaging a rackbar and biassing the tooth to engage the rackbar.

United States Patent Inventor Roll Theiien Wilhelmshaven, Germany Appl.No. 838,149 Filed July 1, 1969 Patented Aug. 31, 1971 Assignee OlympiaWerke Aktiengesellschaft Wilhelmshaven, Germany Priority July 11, 1968Germany 0 10 096 MARGIN STOP MADE OF A SYNTHETIC MATERIAL 6 Claims, 3Drawing Figs.

U.S. Cl 197/70 Int. Cl B4lj 21/04 Field of Search 197/63, 70, 151

References Cited UNITED STATES PATENTS 472,696 4/1892 Blickensderfer197/70 X 9/1903 Myers 197/70 Holden 4.

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Garbell Harmon Dobson Sharpe Suif Mimlitch FOREIGN PATENTS Germany GreatBritain Great Britain ltaly Primary Examiner-Ernest T. Wright, Jr.Attorney-Michael S. Striker ABSTRACT: A margin stop for stopping thepaper carriage of a typewriter in an end position, is constructed as anintegral piece of a synthetic material including a tooth, and a springtongue engaging a rackbar and biassing the tooth to engage the rackbar.

MARGIN STOP MADE OF A SYNTHETIC MATERIAL BACKGROUND OF THEINVENTIONConventional typewriters have a rack bar on which two margin stops aremounted, whose position can be adjusted to determine the end positionsof the paper carriage, and correspondingly the length of a typed line.

Margin stops in accordance with the prior art are constructed of a greatnumber of small parts which are difficult to assemble, and expensive tomanufacture.

. SUMMARY OF THE INVENTION It is one object of the invention to providean inexpensive margin stop of extremely simple construction whichrequires practically no assembly operations.

Another object of the invention is to provide a margin stop whichproduces little noise upon the impact of the returned paper carriage.

With these objects in view, the present invention is concerned with amargin stop which comprises an integral piece, preferably consisting ofa synthetic material.

A margin stop according to a preferred embodiment of the invention hasspaced front and rear portions located on opposite sides of a rack bar,and top and bottom portions connecting the front and rear portions aboveand below the rack bar, respectively. The bottom portion has an upwardprojecting tooth portion and the top portion has a downward projectingresilient portion abutting the top surface of the rack bar for raisingthe bottom portion and the tooth portion to a locked position in whichthe tooth portion engages a recess in the rack bar. The top portion hason top a finger engaging surface so that finger pressure on the samedeforms the resilient portion and lowers the bottom portion with thelocking tooth portion to a position in which the same releases therecess in the rack bar so that the margin stop can slide along the same.

In a modified embodiment, a metal spring is used instead of theresilient portion of synthetic material, and a metal tooth is insertedinto the bottom portion.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional ob jects and advantages thereof,will be best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary perspectivefront view illustrating a margin stop according to one embodiment of theinvention;

FIG. 2 is a fragmentary perspective rear view illustrating the marginstop of FIG. I; and

FIG. 3 is a fragmentary front view illustrating a modified margin stopin accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An integral piece of syntheticmaterial 1 forming a margin stop is mounted on a rack bar 7 having onits bottom face teeth 7a. The term integral piece of synthetic material"is used to denote an integrally molded piece of synthetic material. Arear portion 4 in the form of a flat wall, and a front portion includingtwo front portion parts 5 and 6, and a rectangular cutout 8 between thesame, are located on opposite sides of rack bar 7 slidably engaging thesame. A top portion 2 is located above the rack bar 7 spaced from thesame, and a bottom portion 3 is located below the rack bar 7. Topportion 2 and bottom portion 3 connect front portion 5, 6 and rearportion 4. Top and bottom portions 2 and 3 have inner surfaces boundingcutout 8 on top and bottom.

A resilient portion 9 in the form of an elongated tongue having aprojection 9a at one end, and being integrally connected with topportion 2 at the other end, resiliently abuts with por tion 9a on theupper surface of rackbar 7 to hold the integral piece 1 in theillustrated position in which a tooth portion 10 at one end of bottomportion 3 engages a recess between teeth 7a of rack bar 7. A stop 11cooperating with the corresponding part of the paper carriage, and abell actuating projection 12 are provided at the ends of bottom portion3, integral with the same. i j' The top portion 2 has an upwardlyslanted curved finger-engaging surface 14 ending in a high surface 13,and located above the tooth portion 10. As best seen in FIG. 2, a curvedfulcrum portion 16 is provided at the other-end of bottom portion 3 andis in contact with the teeth 7a of rack bar 7 due to the action of theresilient portion 9 which holds the integral piece 1 in a raisedposition. At the corresponding end of top portion 2, a downwardlyprojecting curved guide portion 15 is provided which abuts the topsurface of rack bar 7. The top portion 2 has end portions 15 and 2a, andthe bottom portion 3 has end portions 16 and 10a connecting the frontportions 5, 6 with the centrally located rear portion 4. Piece 1 has oneend where fulcrum portion 16 and guide portion 15, and another end wheretooth portion 10 and the end 9a of the resilient portion 9 are located.

Due to the fact that curved portions 15 and 16 slidingly engage the top'and bottom surfaces of rack bar 7, the integral piece 1 is guided on therack bar 7, but sliding movement is prevented as long as tooth portion10 engages a recess of the rack bar 7 due -to the action of resilientportion 9. The horizontal bottom surface 17 of end portion 2a of topportion 2 is spaced the distance a from the top surface of rack bar 7,as shown in FIG. 1.

The integral piece 1 serves as a margin stop, and when; the position ofthe integral piece 1 on the rack bar 7 is to be changed, finger pressureis applied in the direction A to the finger engaging surface 14. Due tothe slant of the finger engaging surface 14, the applied pressure hastwo components, namely one component in longitudinal direction of therack bar 7, and another component which is downwardly directed andcauses compression of the resilient portion 9, while the integral piece1 performs a pivotal movement about the fulcrum portion 16 to a lowerposition in which the end portion 10a and the tooth 10 thereon islowered so that the tooth I0 is retracted from the respective engagedrecess permitting sliding of the integral piece 1 along the rack bar 7due to continued finger pressure. When the finger engaging surfaceportion 14 is released, the resilient portion 9 raises portion 10a whilethe integral piece 1 turns again about the fulcrum portion 16 untiltooth 10 engages another recess in the rack bar 7. The curved surface15a of the guide portion 15 permits the angular displacement of theintegral piece 1 while guide portion 15 remains in contact with theupper surface of rack bar 7. An index mark 18 is provided whichcooperates with a graduated scale, not shown, by which the position ofthe integral piece 1 on the rack bar 7 is numerically indicated.

In the modified embodiment of FIG. 3, the integral piece 1', whichconsists of a synthetic plastic material, has portions 2' to 6', and 11'to 16' corresponding to portions 2 to 6, and II to 16 described withreference to FIGS. 1 and 2. However, instead of the integral resilientportion 9, a leaf spring 9' is provided which has a curved centerportion abutting the bottom surface 17' of top portion 2, and two curvedend portions 90 and 9b which resiliently abut the top surface of rackbar 7. The curved end portion 9b matches the contour of the curved guideportion 15, and the end portion 9a has a part engaging the end face ofend portion 2a of top portion 2' so that the spring 9 is secured againstlongitudinal movement along the rack bar 7. Since the tooth 10 of theembodiment of FIGS. 1 and 2 is subjected to great wear, it is replacedby a metal tooth 10 inserted into a slot 10" in the end portion 10a ofbottom portion 3.

When pressure is exerted on the finger engaging surface 14, spring 9' iscompressed, the piece 1' turns about the curved surface of fulcrumportion 16 in clockwise direction as viewed in FIG. 3, until the surface17' abuts the top surface of rack bar 7 so that tooth is retracted fromthe respective recess in rack bar 7, permitting longitudinal sliding ofthe margin stop 1', 9', 10' by finger pressure on surface 14'.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofmargin stops differing from the types described above.

While the invention has been illustrated and described as embodied in amargin stop consisting of an integral piece of a synthetic plasticmaterial, it is not intended to be limited to the details shown, sincevarious modifications and structural changes may be made withoutdeparting in any way from the spirit of the present invention.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

lclaim:

l. Margin stop comprising an integrally molded piece of a syntheticmaterial having spaced front and rear portions with confronting facesfor slidingly engaging the sides of a rack bar, and top and bottomportions connecting said front and rear portions above and below saidrack bar so that said piece surrounds the rack bar, said bottom portionhaving an upward projecting tooth portion, and said top portionincluding a downward projecting resilient portion for engaging the topof the rack bar so that the piece is raised whereby said tooth portionengages the rack bar, said top portion having on top a finger engagingsurface so that pressure on said finger engaging surface moves saidpiece downward whereby said tooth portion is lowered to a positiondisengaged from said rack bar.

2. Margin stop comprising an integrally molded piece of a syntheticmaterial having spaced front and rear portions with confronting facesfor slidingly engaging the sides of a rack bar, and top and bottomportions connecting said front and rear portions above and below saidrack bar so that said piece surrounds the rack bar and has two endsspaced in one direction along the rack bar, said bottom portion havingat one of said ends an upward projecting rounded fulcrum portion, and atthe other of said ends an upward projecting tooth portion, said topportion having at said one end opposite said fulcrum portion a roundeddownward projecting guide portion for sliding on the top of said rackbar, said top portion including an elongated resilient portion connectedat said one end with the bottom of said top portion and projecting insaid onedirection toward said other end of said piece and also downwardfor slidingly engaging the top of the rack bar in the regionof saidother end so that said other end is raised whereby said tooth portionengages the rack bar, said top portion having on top a finger engagingsurface located at said other end so that downward finger pressure onsaid finger engaging surface deforms said resilient portion and turnssaid piece about said fulcrum portion and guide portion whereby saidtooth portion is lowered to a position disengaged from the rack bar.

3. Margin stop as claimed in claim 12 wherein said finger engagingsurface is slanted upward toward said one end so that the margin stopcan be moved along said rack bar by finger pressure in said onedirection after downward finger pressure has disengaged said toothportion from the rack bar.

4. Margin stop as claimed in claim 2 wherein said front portion has twofront portion parts and a cutout between said two front portion parts;and wherein said rear portion is located opposite said cutout; andwherein said top and bottom portions have end parts integrally connectedwith said two front portion parts and central parts integrally connectedwith said rear portion.

5. Margin stop as claimed in claim 4 wherein one of said end parts ofsaid bottom portion includes said tooth portion, and wherein the otherof said end parts of said bottom portion has said fulcrum portionprovided with a curved fulcrum surface.

6. Margin stop as claimed in claim 2 wherein said bottom portion has anintegral stop projection and an integral bell actuating projectionspaced in said one direction along the rack bar.

1. Margin stop comprising an integrally molded piece of a syntheticmaterial having spaced front and rear portions with confronting facesfor slidingly engaging the sides of a rack bar, and top and bottomportions connecting said front and rear portions above and below saidrack bar so that said piece surrounds the rack bar, said bottom portionhaving an upward projecting tooth portion, and said top portionincluding a downward projecting resilient portion for engaging the topof the rack bar so that the piece is raised whereby said tooth portionengages the rack bar, said top portion having on top a finger engagingsurface so that pressure on said finger engaging surface moves saidpiece downward whereby said tooth portion is lowered to a positiondisengaged from said rack bar.
 2. Margin stop comprising an integrallymolded piece of a synthetic material having spaced front and rearportions with confronting faces for slidingly engaging the sides of arack bar, and top and bottom portions connecting said front and rearportions above and below said rack bar so that said piece surrounds therack bar and has two ends spaced in one direction along the rack bar,said bottom portion having at one of said ends an upward projectingrounded fulcrum portion, and at the other of said ends an upwardprojecting tooth portion, said top portion having at said one endopposite said fulcrum portion a rounded downward projecting guideportion for sliding on the top of said rack bar, said top portionincluding an elongated resilient portion connected at said one end withthe bottom of said top portion and projecting in said one directiontoward said other end of said piece and also downward for slidinglyengaging the top of the rack bar in the region of said other end so thatsaid other end is raised whEreby said tooth portion engages the rackbar, said top portion having on top a finger engaging surface located atsaid other end so that downward finger pressure on said finger engagingsurface deforms said resilient portion and turns said piece about saidfulcrum portion and guide portion whereby said tooth portion is loweredto a position disengaged from the rack bar.
 3. Margin stop as claimed inclaim 12 wherein said finger engaging surface is slanted upward towardsaid one end so that the margin stop can be moved along said rack bar byfinger pressure in said one direction after downward finger pressure hasdisengaged said tooth portion from the rack bar.
 4. Margin stop asclaimed in claim 2 wherein said front portion has two front portionparts and a cutout between said two front portion parts; and whereinsaid rear portion is located opposite said cutout; and wherein said topand bottom portions have end parts integrally connected with said twofront portion parts and central parts integrally connected with saidrear portion.
 5. Margin stop as claimed in claim 4 wherein one of saidend parts of said bottom portion includes said tooth portion, andwherein the other of said end parts of said bottom portion has saidfulcrum portion provided with a curved fulcrum surface.
 6. Margin stopas claimed in claim 2 wherein said bottom portion has an integral stopprojection and an integral bell actuating projection spaced in said onedirection along the rack bar.